NUC RAD SHARE

CHEST RADIOLOGY

 
HRCT Hi res CT

CHEST PATTERNS & DIFFERENTIALS

 

>>CHEST BY NUMBERS

1.     Chest measurements

a.     Carina at T4-5; normal carina angle 60-100deg

b.     Interlobar artery <16mm

c.      MPA <3cm

d.     Left hila 1-2cm higher than highest point of right hila

e.     R paratracheal stripe ≤5mm

f.      Vascular pedicle= 38-58mm (should be <7cm otherwise widened mediastinum) on PA view (measure near level azygous vein; from where SVC meets RMSB and to where a perpendicular line is drawn from left subclavian exiting Ao arch)

g.     Azygous trans dia <1cm upright and <1.5cm supine

h.     Kids humeral head ossific center at >37wks (term); femoral head ossific center at 4mos

i.       Kids normal 6ribs ant and 8ribs post  (hypeinflation 8ribs ant/10ribs post; hypoinflation 4ribs post)

j.       Normal thymus (homogenous, bilobed/triangular with concave lateral margins on CT; size increases from birth to age 8yo then decreases; 18mm thickness <20yo and 13mm in older pts; rebound thymic hyperplasia if volume increases by 50%)—sail sign (right) or wave sign (smooth indentations)

k.      Thoracic aorta (ectasia 3.7-4.0cm, mild enlargement 4.0-4.5cm, ≥4.5cm aneurysm, ≥6cm surgery)

                                                  i.     LVOT

                                                 ii.     Aortic annulus (at valve)

                                                iii.     Aortic root (SOV)

1.     “Cusp to cusp” measurement (cardiologists) upto 4cm

2.     Mean “cusp to commisure” (preferred)

                                                iv.     Sinotubular jct (STJ)

                                                 v.     Asc aorta (@MPA) upto 3.7cm

                                                vi.     Aortic arch

                                              vii.     Aortic isthmus (btwn take off of left subclavian artery and ductus arteriosus)

                                             viii.     Prox desc aorta (@MPA)

                                                ix.     Distal desc aorta (@dia hiatus) upto 2.8cm

l.       Normal pericardial thickness=2mm (>4mm is concerning for pericarditis)

m.    Pericardial fluid: normal 15cc (post CPA blunting with >75cc, lat CPA blunting with >250cc, complete opacification atleast 500cc); >1cm decub free-flowing eff can be tapped without imaging guidance

n.     Left Atrium AP <4cm

o.     Left Ventricle chamber transverse in ED <5cm

p.     LV wall thickness <12mm

q.     Haller index of pectus excavatum (transverse dia divided by AP diameter) normal ≤2.5 (>3.2 is one criteria for surgical correction)

r.      PTX >25% requires chest tube evacuation (calculator= ww.chestx-ray.com/calculator)

s.      Normal dia excursion of 1-2ribs on fluoro sniff test (unless there is mod to large effusion)

 

2.     Lines/Tubes (“correlate for preferred/desired location/placement”)

a.     ETT= 2-6cm above carina and atleast 3cm below vocal cords (carina is usually at about T6; vocal cords at C6)—should be below inf aspects of clavicles (thoracic inlet); cuff <3cm in dia (without bowing of tracheal walls); tube dia should be 2/3 of tracheal dia

b.     Trach tube= should be halfway btwn neck entrance site and carina

c.      SGC (for pulm capillary WP)=tip should be distal to pulmonic valve; on the right, measure from where catheter crosses itself and should be within 2cm (should next extend beyond proximal interlobar pulm artery); on the left, measure from most sup turn of catheter at hila and should be within 2cm

d.     Pacer/AICD (all are pacers; AICD has sensing and shocking electrodes for cardioversion/defibrillation)

                                                  i.     Single lead= RV; Dual lead= RA and RV; Triple lead (biventricular for CRT)=RA, RV, and coronary sinus

                                                 ii.     Battery can with lead pins; leads

                                                iii.     Look for broken lead (lead damage); dislodged lead tip (pulled back); Twiddler’s syndrome

e.     IABP (intra-aortic counterpulsion balloon pump for cardiogenic shock)=inflates during diastole; radiopaque tip 1cm distal to left subclavian; projecting 1-2cm below top of arch

f.      Chest tube (pleural drain, thoracostomy tube, pigtail cath)=tip and side ports within thoracic cavity; anterosuperior placement for PTX; posteroinferior placement for effusion; exclude tube within fissure or intra-pulmonary placement

g.     NGT/OGT (enteric tube)=tip within stomach, distal to GEJ (side port is located 6cm from the tip); note if coiled or post-pyloric

h.     DHT (feeding tube)=weighted tip should be within 2nd or 3rd portion of duo (prefer near distal 4th portion of duo neat LOT)

i.       CVC (tunneled dialysis cath, PICC, port-a-cath (chest ort) with Huber needle access)=IJ/subclavian/femoral; tip near superior cavo-atrial junction or caudal aspect of SVC; should be medial to 1st rib on frontal and caudal and posterior to clavicle (otherwise suspect intra-arterial)

j.       UVC= umbilicusàUVàleft PVàductus venosusàIVC; tip at or slightly above dia at inf cavo-atrial jct; curves medially (convex laterally) thru liver on frontal; on lateral view, directed ant-sup then horiz-post and then heads sup towards heart

k.      UAC= umbilicusàUAàinternal iliacàcommon iliacàaorta (ascends parallel to spine); normal high=T6-T9 (above dia); normal low=below L2 (more complications if at L1-2 level of renal arteries); dips inferiorly then ascends superiorly parallel to spine

l.       Epicardial leads

m.    Implantable loop recorder (for rhythm)

n.     Neurostimulator with epidural leads/electrodes

o.     ECMO (extra-corporeal membrane oxygenation) in kids

                                                  i.     VV (veno-venous) vs VA (veno-arterial)

                                                 ii.     VV=Draining large venous cannula via RIJ (make sure tip and side port within RA); smaller returning venous catheter via femoral vein (tip within IVC at or above inferior cavo-atrial jct)

                                                iii.     VA=also has an arterial returning cannula usually within R CCA (tip projects over arch at origin of innominate artery)

                                                iv.     Normal to have diffusely opacified lungs

p.     VAD (ventricular assist device)—bridge to cardiac transplant

                                                  i.     Percutaneous vs surgically implanted

                                                 ii.     LVAD, RVAD, BIVAD

                                                iii.     Conduits (inflow vs outflow), pump, driveline

                                                iv.     Look for kinking of cannula/conduit

                                                 v.     Percutaneous VAD (Impella): tip within LV; outflow portion within LVOT

 

>>SPN

1.     Solid nodules

a.     Size: 1-3mm=miliary; 3-5mm=micronodule; >5mm=macronodule; >3cm=mass

b.     B9 calc= central, diffuse, laminated (concentric), popcorn

c.      Malig calc= eccentric, stippled, amorphous

d.     Margins= smooth, lobulated (bad), spiculated (bad)

e.     Attenuation= fat (<-40HU) suggests hamartoma

f.      Location= subpleural, juxtapleural, perifissural, pleural-based, along mediastinal pleural surface, peribronchovascular, endobronchial

g.     Others=satellite nodule suggest infx; pleural tag (bad); central lucency (aka ABG) ddx is BAC, lymphoma, OP

h.     Enhancement <15HU is likely benign (>20-25HU is probably malignant ~98% sensitive for CA)

i.       Volume Doubling Time= increase in dia by 25% correlates with doubling of volume (malig VDT usually btwn 30-500d)àsee calculator on chestxary.com

j.       DDX solid non-calcified nodule=non-calcified granuloma, intrapulm LN, CA

k.      DDX airspace/macrondules nodules= acute varicella (classic), mets, fungal, aspergillosis, kaposi

l.       DDX calcified micronodules= fungal (histo)/TB, alveolar microlithiasis, malig calcifications, healed varicella, silicosis, mets

m.    DDX cavitating mets= primary SCC, secondary SCC (H&N males and cervical females), sarcoma  

n.     DDX calcifying mets= osteo/chondrosarcoma, mucinous colon, leimyosarcoma

o.     DDX cannon-ball mets (>3cm)= MCSaR melanoma, colon, sarcoma, RCC

p.     DDX nodules with GG halo (hemorrhagic)= hemorrhagic mets (chorioCA), invasive aspergillosis, kaposi, CMV

q.     DDX mets in kids= T-ROWEN testicular, rhabdomyosarcoma, osteosarcoma, wilms, ewings, neuroblastoma

r.      DDX nodules in HIV= TB/fungal, CMV (GG), Kaposi (flame-shaped), aspergillosis (GG halo), PCP (cystic UL), lymphoma

s.      PET/CT: size 8mm; low (<5%) to mod (5-60%) prob or CA; not for very low prob or high prob; discordance btwn pretest prob and imaging test; for staging

t.      PET/CT sensitivity for BAC is 10-30% and false neg rate for carcinoid is 25%

u.     PET/CT overall sens 97% and spec 80% for characterizing SPN >1cm in dia

v.      NLST NEJM 2011 LDCT for lung CA screening “reduced lung CA mortality by 20% with LDCT vs CXR screening

w.    High risk pts per Fleischner society=smoker, 1st deg relative with lung CA, exposure to asbestos/radon/uranium

x.      Fleischner society criteria does not apply to: age<35yo, known/suspected extra-thoracic CA, infectious symptoms (unexplained fever), non-solid nodules

y.      Screening chest CT criteria (ACR): 55-80yo with 30pack-yr smoking hx who is current smoker or quit 15yr ago

 

2.     Non-solid nodules

a.     GGN (pure GG nodule)

                                                  i.     Ddx= atypical adenomatous hyperplasia (precursor to adenoCA) vs AdenoCA (BAC) vs infx/inflammatory vs focal fibrosis

                                                 ii.     <5mm don’t need f/u esp if enrolled in lung nodule program; but if multiple (then do FU in 1yr)

                                                iii.     5mm FU in 3-6 mos à if stable FU for total of 3-5yr vs if enlarge or develop solid component recc resection

b.     PSN (part-solid nodule)

                                                  i.     FU in 3-6mos à if persist consider PET/CT (some say resect) vs if enlarge recc resection

 

3.     SCREENING CHEST CT  

a.     NLST (national lung screening trial)

b.     Published 2011 in NEJM (“Reduced lung cancer mortality with low-dose CT screening”)

c.      Pts who received low dose CT had 20% lower risk of dying from lung CA than those who received CXR

d.     Screening chest CT criteria (ACR): 55-80yo with 30pack-yr smoking hx who is current smoker or quit 15yr ago

e.     What is considered low dose CT

                                                  i.     Prefer ≥16 detector CT with gantry rotation time ≤0.5s

                                                 ii.     Slice thickness ≤2.5mm (with recon interval ≤ slice thickness) and use ≤1mm for MPRs

                                                iii.     End-inspiration

                                                iv.     Non-contrast

                                                 v.     CTDI vol ≤3mGy for “standard” size pt (DLP ≤75mGy-cm or Est dose ≤1mSv)

f.      Reporting

                                                  i.     Use Lung-RADs version1

                                                 ii.     Size (measure on lung windows; give avg dia & round it to nearest whole number)

                                                iii.     Location (lobe/seg)—give image#

                                                iv.     Attenuation (soft tissue, calcified, mixed)

                                                 v.     Opacity (solid, part-solid, GG)

                                                vi.     Margin (smooth, lobulated, spiculated)

                                              vii.     Comparison (compare to oldest scan)—increase in size by >1.5mm is significant

      

>>AIRWAYS (see HRCT for small airways dz and bronchiolitis)

                         1.     Airways thickening on CXR (cheerios and dirty lung): non-specific findings seen with reactive-airways disease (asthma) vs sequel of smoking vs bronchitis(clinical diagnosis)

                         2.     Airways lesions

a.     B9 solitary=mucus plug, FB, papilloma (multiple in kids; malig transformation to SCC in 10% of adults)

b.     Multiple airways lesions=papillomatosis, mets, TBO/RP/amyloidosis, TB

c.      Malignant Trachea=”SAM”  SCC, adenoid cystic, mets (breast, melanoma)

d.     Malignant Bronchus=”BCMM”  bronchogenic tumor (SCC, small cell), carcinoid (enhances, 1/3calcified, tip-of-iceberg), mucoepidermoid, mets (breast, melanoma)

                        3.     Unilateral collapsed lung= central obstructive lesion (bronchogenic CA, endobronchial tumor, FB), pneumonectomy, unilateral lung agenesis/hypoplasia, pulmonary artery atresia/hypoplasia

                        4.     Focal tracheal stricture=Extrinsic compression (PA sling with napkin-ring tracheal rings), prolonged intubation scarring, endobronchial TB (multiple stenosis), amyloidosis (does not spare post membrane), wegner’s, CA

                        5.     Finger-in-glove=CF, ABPA (asthma), bronchial atresia, central malignancy with distal plugging

                        6.     Unilateral hyperlucent lung

a.     Don’t miss: PTX, PE (ologemia), FB (RLL>LLL)

b.     CLE (LUL>RML>RUL), bronchial atresia

c.      Bronchiolitis Obliterans (Swyer james in kids <8yo)

d.     Poland’s, unilat mastectomy, large bulla (emphysema)

 

>>MEDIASTINUM

1.     Lymph nodes stations (IASLC 2009)

a.     1=supraclavicular (low cervical)

b.     2R/L=upper paratracheal

c.      3A/P A=prevascular (ant mediastinal and ant  to left brachicephalic vein); P=prevertebral  (retrotracheal)

d.     4R/L=lower paratracheal

e.     5=subaortic (AP window)

f.      6=para-aortic (phrenic)

g.     7=subcarinal

h.     8=para-esophageal (below carina)

i.       9=pulm ligament

j.       10R/L=hilar

k.      11R/L=interlobar

l.       12/13/14R/L=lobar/segmental/subsegmental (peribronchial)

 

2.     Mediastinal lesions

a.     Ant med mass

                                                  i.     Thymus

1.     Thymic hyperplasia (rebound s/p chemo/xrt >50% increase in vol above baseline; Myasthenia gravis=85% hyperplasia and 15% thymoma)

2.     Thymic cyst (unilocular/multilocular; may have peripheral calc)

3.     Thymolipoma (b9, soft tumor that drapes down and may change shape w/ decub)

4.     Thymoma (middle age pts;  b9=encapsulating with homogenous enhancing capsule, may have lobulated contours and can be cystic VS invasive=malignant with irreg margins, invasion/encasement of mediastinal fat and may have drop mets into pleura or pericardial involvement; assoc with MG=40% w/ thymoma have MG and 10-15% with MG have thymoma; can be cystic w/ mural nodule; 5% may have calcs)

5.     Thymic CA (no capsule; can be metastatic--assoc w/ mediastinal lymphadenopathy which is uncommon with thymoma; poor prognosis)

                                                 ii.     Teratoma and other germ cell tumors (<20yo; mature/immature/malig)

                                                iii.     Terrible lymphoma (homogenous mass which encases vessels; HD vs NHL)

                                                iv.     Thyroid substernal goiter

                                                 v.     Mets (neuroblastoma)

                                                vi.     Fibrosing mediastinitis (TB, histo)

                                              vii.     Mediastinal lipomatosis (steroids, obese, cushing’s=endogenous steroids)

b.     Cystic med mass

                                                  i.     Duplication (enteric/neuroenteric) vs bronchogenic cyst (subcarinal)

                                                 ii.     Pericardial cyst (R>L)

                                                iii.     Thymic cyst (unilocular/multilocular; may have peripheral calc)

                                                iv.     Cystic thymoma (can have mural nodule)

                                                 v.     Teratoma (<20yo; look for fat, fat-fluid level, calcification)

c.      Fatty med mass

                                                  i.     Epicardial fat pad

                                                 ii.     Mediastinal lipomatosis

                                                iii.     Thymolipoma

                                                iv.     Teratoma

                                                 v.     Hernia (morgagni usually on the right; omental fat)

d.     Calcified med mass

                                                  i.     Fibrosing mediastinitis (TB, histo; SVC syndrome, pulm HTN)

                                                 ii.     Treated lymphoma

                                                iii.     Teratoma (<20yo; contains fat)

                                                iv.     Thyroid substernal goiter

                                                 v.     Calcified nodes= TB , sarcoid/silicosis (egg-shell calcs)

e.     Cardiophrenic angle mass

                                                  i.     Epicardial fat pad

                                                 ii.     Pericardial cyst

                                                iii.     Duplication cyst

                                                iv.     Thymolipoma

                                                 v.     Epiphrenic LN

                                                vi.     Hernia

f.      Paraspinal mass

                                                  i.     Neuroenteric cyst (w/ vertebral anomaly)

                                                 ii.     Neurogenic tumor (schwannoma, NF, paraganglioma, neuroblastoma)

                                                iii.     Extramedullary hematopoiesis

                                                iv.     Duplication or bronchogenic cyst

                                                 v.     Descending aortic aneurysm

 

3.     Vascular anomalies

a.     Bovine arch

b.     Double arch (R arch is larger/higher/posterior than L with midline trachea and descending left aorta; encircles trachea and eso in a tight complete ring)

c.      Right arch

                                                  i.     Higher assoc with truncus but TOF overall more common

                                                 ii.     2 types: mirror image(worse b/c assoc cardiac anomalies like truncus or TOF)  vs R arch with aberrant LS

                                                iii.     Can be complete ring if intact lig arteriosus or open PDA

d.     Aberrant subclavian (travels post to eso)

                                                  i.     L arch with aberrant R subclavian (dysphagia lusoria; diverticulum Kommerell)

                                                 ii.     R arch with aberrant L subclavian

e.     Pulmonary sling (LPA arising from RPA; travels btwn trachea and eso; retrotracheal density more caudal than aberrant subclavian; napkin-ring tracheal rings)

f.      Cervical arch

g.     Anomalous vessel lateral to aortic arch

                                                  i.     PAPVR

                                                 ii.     Persistent left SVC (left common cardinal vein starts near jct of SC and IJ, descends lateral to aortic arch and anterior to left hilum, courses post wall of LA, and dumps into coronary sinus)

h.     Enlarged azygous vein (note: azygous of rightàin SVC; hemiazygous of leftàinfo brachiocephalic vein)

                                                  i.     Azygous continuation of IVC

                                                 ii.     CHF

                                                iii.     TR

                                                iv.     Constrictive pericarditis

                                                 v.     SVC obstruction distal to azygous entry

                                                vi.     Portal HTN

i.       Heterotaxy syndrome

                                                  i.     Asplenia

                                                 ii.     Polysplenia

 

4.     Aorta

a.     Aneurysm

                                                  i.     Thoracic aorta (ectasia 3.7-4.0cm, mild enlargement 4.0-4.5cm, ≥4.5cm aneurysm, ≥6cm surgery)

1.     LVOT

2.     Aortic annulus (at valve)

3.     Aortic root (SOV)

a.     “Cusp to cusp” measurement (cardiologists) upto 4cm

b.     Mean “cusp to commisure” (preferred)

4.     Sinotubular jct (STJ)

5.     Asc aorta (@MPA) upto 3.7cm

6.     Aortic arch

7.     Aortic isthmus (btwn take off of left subclavian artery and ductus arteriosus)

8.     Prox desc aorta (@MPA)

9.     Distal desc aorta (@dia hiatus) upto 2.8cm

 

                                                 ii.     Ectasia vs true aneurysm (fusiform vs saccular)

                                                iii.     Sinus of valsalva aneurysm >4cm

                                                iv.     Annuloaortic ectasia (tulip bulp; Marfans or ED)

                                                 v.     Post-stenotic dilation secondary to aortic stenosis

                                                vi.     Syphilis aortitis (calcifications)

                                              vii.     Mycotic aneurysm (saccular with surrounding inflammation)

                                             viii.     Ductus bump or diverticula (anteromedial; gentle obtuse bulge as opposed to sharp acute margins of pesudoaneurysm)

                                                ix.     Traumatic pseudoaneurysm (acute margins with aorta; saccular without atheroma; at aortic isthmus; s/ trauma)

                                                 x.     Infundibulum of aortic arch/branch vessels

b.     Intra-mural hematoma (within aortic wall; hyperdense crescent on non-contrast CT; better prognosis if <2cm; treat it like focal dissection)

c.      Mural thrombus (within aneurysm) vs eccentric/ concentric intraluminal thrombus 

d.     Penetrating aortic ulcer (PAU; thru existing atheroma and projecting beyond aortic wall)

e.     Ulcerative plaque (does not project beyond aortic wall)

f.      Dissection

                                                  i.     Stanford A=asc aorta (60%); Stanford B=begins beyond brachiocephalic vessels (40%)

                                                 ii.     CXR: widened mediastinum, double or irreg aortic contour, inward displacement of athero calcs

                                                iii.     Intimal flap

1.     True lumen (smaller b/c compressed by false lumen; surrounded by intimal calcification; brighter lumen)

2.     False lumen (larger b/c higher pressure; beak sign=wedges around true lumen; cobweb sign=linear media remnants; lower contrast density if patent due to delayed opacification; may be completely/partially thrombosed or contain thrombus)

                                                iv.     Complications

1.     Aortic rupture

2.     Coronary artery occlusion (acute MI usually involves RCA)

3.     Aortic valve incompetence (acute aortic insufficiency)

4.     Rupture into pericardial sac with cardiac tamponade

5.     Extension into arch/branch vessels with or without occlusion

a.     End-organ perfusion compromise

b.     Ischemic stroke

c.      Limb ischemia

d.     Paraplegia (artery of adamkiewicz to anterior spinal artery)

                                                 v.     Chronic dissection flap (thicker, straighter and may be calcified)

                                                vi.     Intramural hematoma is a variant

                                              vii.     Acute aortic injury

1.     CXR: widened mediastinum, indistinct/irreg aortic contour, deviation of trachea to right, depression of LMSB, left apical pleural cap, thickened paraspinal stripe

2.     Location: isthmus (most common; located btwn left subclavian artery and lig arteriosus)>asc aorta=desc aorta at dia hiatus

3.     Findings: irreg aortic contour with mural hematoma; laceration/transection with active extravasation of contrast; pseudoaneurysm; peri-aortic/mediastinal hematoma (+/- pericardial/pleural hematoma); focal intimal flap/clot; look for concomitant left subclavian artery injury

4.     Ddx=ductus bump or diverticula

 

5.     Cardiac

                                                  i.     LAE= oblique measurement from LA border (double density) to mid point of LMSB >7cm on PA view; slayed carina >90-100deg; walking man sign of posteriorly displaced LMSB on lateral view

                                                 ii.     LVE=Hoffman rigler sign (LV extends more than 1.8cm beyond posterior border of IVC at 2cm cephalad from intersection of LV and IVC on “true” lateral)

                                                iii.     RAE=not well discernable on CXR

                                                iv.     RVE=upper tipped “boot-shaped” apex; filling of retrosternal clear space; enlarged MPA

                                                 v.     Acute MR=RUL edema

                                                vi.     Sig PS=left PA enlargement

                                              vii.     Sig AS=asc aorta enlargement (look for valvular calcifications)

                                             viii.     LV aneurysm

1.     True=post-MI; wide neck; may contain thrombus; usually inferolateral wall

2.     False=post-trauma (aka pseudoaneurysm); narrow neck; may rupture; usually posterolateral wall; less common

                                                ix.     Cardiac mass

1.     Thrombus (bland vs tumor)

2.     Metastasis (esp ACC, HCC, RCC, Hepatoblastoma and Wilm’s)—10-20x more common than primary cardiac tumor

3.     Primary cardiac tumor

a.     B9=myxoma (LA>RA), rhabdomyoma (kids w/ TS); hemangioma (T2 bright); fibroma (kids)

b.     Malig=angiosarcoma (#1), rhabdosarcoma (#2)

                                                 x.     Pericardial effusion= infection (TB, viral), uremia, CVD (SLE, RA), mets, post-MI/post-pericardiotomy (dressler’s syndrome usually after2wks—also assoc with pleural effusion and parenchymal opacities)

 

6.     Chest wall/pleura

a.     Rib lesion= “FAME”  fibrous dysplasia, ABC, mets/myeloma, EG, enchondroma

b.     Chest wall mass= hematoma, primary or met bone tumors (consider askin’s, ewing’s, EG, neuroblastoma in kids; don’t forget chondrosarcoma) hematoma,  fibrous dysplasia, schwannoma/NF, fibrosarcoma/MFH, OM, elastofibroma dorsi

c.      Pleural mass or encasement= empyema (split pleura sign), loculated effusion, fibrothorax (TB), mesothelioma, mets (breast/melanoma), lymphoma, invasive thymoma (co-exiting ant med mass), fibrous tumor of pleura (focal)

d.     Pleural calcifications= asbestos exposure, old hemothorax/empyema, fibrothorax (TB)

e.     PTX=asthma/COPD, trauma, EG/LAM, sarcoma mets, catamenial, , barotrauma, spontaneous

 

7.     LUNG CA (stage IIIB is unresectable)

a.     Incidence: AdenoCA>SCC>BAC>Small cell (AFIP)

b.     Prognosis: SCC>Large cell>BAC>AdenoCA>Small cell

 

c.      Small Cell

                                                  i.     Smokers

                                                 ii.     Unresectable

                                                iii.     Paraneoplastic syndromes (hypercalcemia, cushing, SIADH) with oat cell subtypes

                                                iv.     Centrally located (extensive LAD may result in SVC syndrome)

                                                 v.     Staging: “limited dz” (confined to tolerable radiation port incld supraclavicular node, regional mediastinal, or effusion) vs “extensive dz”

 

d.     Non-small cell

                                                  i.     AdenoCA

1.     Non-smoker women

2.     Peripherally located

3.     Subtype=BAC, scar carcinoma

                                                 ii.     SCC (epidermoid)

1.     Smokers

2.     Centrally located (around airways but not within it unlike small cell)

3.     May cavitate

4.     Dysplasiaàin-situàSCC

5.     Good prognosis (b/c slow growing)

6.     Subtype=pancoast (superios sulcus tumor) w/ SVC syndrome, horner’s, brachial plexopathy, dysphagia

                                                iii.     Large cell

1.     Rapid growth

2.     Peripherally located

e.     Staging

                                                  i.     Size (2cm, 2.1-3cm, 3.1-5cm, 5.1-7cm)

1.     Size>7cm (T3)

                                                 ii.     Location

                                                iii.     Multicentric tumor (synchronous) of same histology

1.     Satellite nodule in same lobe (T3)

2.     Nodule(s) in different ipsilateral lobe (T4)

3.     Contralateral lung nodule(s) i.e. intrathoracic met (M1a)

                                                iv.     Aggressive features

1.     Direct visceral pleural invasion (T2)

2.     Direct parietal pleural invasion aka chest wall (including superior sulcus tumors), diaphragm, phrenic nerve, mediastinal pleura, and/or parietal pericardium (T3)

3.     Invasion of mediastinum, heart, great vessels, carina, trachea, eso, vertebral body, recurrent laryngeal nerve (T4)

                                                 v.     Endobronchial lesion

1.     Endobronchial lesion not proximal to lobar bronchus (T1)

2.     Endobronchial lesion ≥2cm from carina or complete atelectasis/post-obstr pneumonitis extending to hilum but not involving entire lung (T2)

3.     Endobronchial lesion <2cm from carina or partial atelectasis/post-obstr pneumonitis involving entire lung (T3)

4.     Endobronchial lesion with involvement of carina (T4)

                                                vi.     Nodal involvement

1.     N1=ipsilateral hilar or peribronchial

2.     N2=ipsilateral mediastinal and subcarinal

3.     N3=contralateral hilar/mediastinal; supraclavicular; scalene

                                              vii.     Malignant effusion i.e. pleural dissemination or pleural nodules (not direct pleural invasion) and/or Malignant pericardial effusion (M1a)

                                             viii.     Distant (extrathoracic) met (M1b)

 

>>HRCT

a.     History and Labs

                                                  i.     Age (20-40yo=sarcoid, EG, CVD; consider IPF in >50yo)

                                                 ii.     Sex (LAM exclusively in women)

                                                iii.     Smoking hx (smokers=EG, RB/RBILD/DIP; non-smokers=HP, sarcoidosis)

                                                iv.     Time course (acute onset=AIP)

                                                 v.     Family hx (LAM, sarcoidosis)

                                                vi.     Exposure/toxins (pets/hobbies/occupation/home environment)

                                              vii.     CVD (RA, scleroderma etc)

                                             viii.     Malignancy

                                                ix.     Symptoms (no extrapulm sxs in IPF; CP pleurisy in CVD)

                                                 x.     Labs (PFTS with DLCO, ANA, RF, ANCA, anti-BM ab, cryoglobulins, hypersensitivity panel)

b.     Location/distribution

                                                  i.     Focal vs patchy vs diffuse

                                                 ii.     Upper, middle, lower lobe pre-dominant (vs panlobar)

                                                iii.     Peripheral vs central vs peribronchovascular (sarcoid, lymphangitic spread, LIP, lymphoma or lymphoproliferative d/o, amyloid)

                                                iv.     Reticular, reticulonodular, micronodular

                                                 v.     What is “fibrosis”? intra-lobular septal thickening (fine reticulation), traction bronchiectasis, honeycombing all are considered fibrosis

 

c.      Lines

                                                  i.     Peripheral reticular pattern  if lower lobe predominant

1.     UIP

2.     Fibrotic NSIP assoc with chronic CVD (esp scleroderma) and RA (distal clav absorption)

3.     Drug toxicity (BAM=bleomycin, amiodarone, methotrexate)

4.     Asbestosis (parenchymal bands and curvilinear subpleural lines)

5.     Chronic emphysema (smoking-related interstitial dz)

                                                 ii.     linear pattern (aka lines radiating from hila +/- kerley lines) “LIFE”

1.     Lymphagitic spread

2.     (Atypical) infection like viral/mycoplasma

3.     Fibrosis like IPF

4.     Edema

                                                iii.     Septal thickening

1.     Intra-lobular (fine reticular=fibrosis)

2.     Inter-lobular septal thickening (secondary lobules)—if not the predominant finding, can ignore this!!

a.     Smooth septal thickening (water=edema, pus=infx, blood=hemorrhage, protein=PAP)

b.     Nodular septal thickening (sarcoid, lymphangitic spread, LIP, lymphoma or lymphoproliferative d/o, amyloid)

c.      Irregular (any fibrosing lung dz)

                                                iv.     Subpleural lines or parenchymal bands (scarring/fibrosis, atelectasis, asbestosis)

 

d.     Nodules

                                                  i.     Micronodules (<3-5mm)

1.     Centrilobular (evenly spaced, don’t extend to pleura or fissure)

a.     GG (ill-defined)

                                                                                                            i.     HP subacute in non-smoker (classic), hemosiderosis

                                                                                                          ii.     RB or RBILD in smokers (“subtle GG nodules” in smokers)

                                                                                                         iii.     Associated with NSIP (CVD) and OP/COP

b.     Solid with TIB (90% infectious bronchiolitis)

                                                                                                            i.     Think inflammatory /infectious bronchiolitis vs Aspiration

1.     STAB= smokers, TB/MAI, Aspiration, Bronchiolitis, BAC (endobronchial adenoCA), BronchoPNA (patchy clustered nodules)

                                                                                                          ii.     If central mucus plugging (finger-in-glove), consider asthma, CF, ABPA

                                                                                                         iii.     Mimicker=tumor emboli (branching tumor in enlarged vessel in peribronchovascular distribution)

                                                                                                         iv.     AIDS-related airways disease

                                                                                                          v.     Endobronchial mucinous adenoCA (BAC)

c.      Solid without TIB

                                                                                                            i.     Pneumoconiosis/Silicosis (look for PMF etc)

                                                                                                          ii.     EG (aka pulm LCH)--if nodules are dense; may cavitate

2.     Perilymphatic (patchy and abut pleura and fissure)

a.     Sarcoid, lymphangitic spread, LIP, lymphoma or lymphoproliferative d/o, amyloid

3.     Random (aka miliary; diffuse/uniform unlike perilymphatic)

a.     METS-B=hematogenous mets (thyroid/renal/melanoma), EG, miliary TB/fungal/disseminated viral, sarcoid/silicosis, BAC

                                                 ii.     Branching nodules within enlarged vessel in peribronchovascular distribution = consider tumor emboli

 

e.     GGO (can see vessels thru it)

                                                  i.     Differential similar to consolidation

                                                 ii.     “ABCDEH”= PAP, BOOP/COP, PCP, DIP, Drugs, Edema, HP, Hemorrhage

                                                iii.     Acute  vs chronic

1.     Acute GGO

a.     Edema (CHF and in ICU pts consider ARDS/DAD/AIP)

b.     Hemorrhage (hemosiderosis)

c.      Atypical infx (PCP in AIDS and CMV in post-transplant)

d.     Subacute HP (“head-cheese”)

2.     Chronic GGO

a.     PAP (“crazy paving”=geographic GG with septal thickening), PCP (UL cysts and perihilar GG in HIV pt)

b.     BOOP/COP (peribronchial and subpleural “polygonal” fleeting consolidations, GGO, and nodules)

c.      DIP and NSIP

d.     Drugs (BAM=bleomycin, amiodarone, methotrexate)

e.     HP (exposure)

f.      BAC

                                                iv.     Crazy paving ddx= PAP, pulm edema, pulm hemorrhage, PNA (bacterial), BAC

                                                 v.     History helps

1.     Hemoptysis=hemorrhage

2.     Immunocompromised=infx (PCP)

3.     Exposure=HP (non-smoker)

4.     CVD or ILD=alveolitis

 

f.      Mosaic attenuation

                                                  i.     How to tell from GGO=Geographic (sharply demarcation on inspiratory view), differential vessel size (smaller in lucent areas), air-trapping (on expiration dark areas remain dark), stable over time

                                                 ii.     Note: Mosaic attenuation is an INSPIRATORY HRCT finding while air-trapping is a EXPIRATORY HRCT findings!!

                                                iii.     small airways disease vs small vessel disease à do expiratory view to distinguish btwn the two

                                                iv.     SMALL VESSEL DISEASE (less common) =no air-trapping; larger areas of non-lobular lucencies with normal vessel size; pulm HTN and R heart enlargement

1.     Chronic PE (look for associated pulm HTN)

2.     Vasculitis (CVD)

                                                 v.     SMALL AIRWAYS DISEASE =with air-trapping; lobular areas of lucencies with small vessel size; peribronchial thickening;

1.     Direct signs of small airways dz=bronchial wall thickening, bronchiolectasis, centrilobular nodules with TIB

2.     Indirect signs of small airways disease dz= mosaic attenuation (described in inspiration), air-trapping (described in expiration; mosaic attenuation persists and contours get even more sharply marginated)

3.     Bronchiolitis

a.     Smokers (RB, RBILD)

b.     Infectious (viral in kids like RSV/adenovirus/mycoplasma; MAC/TB/fungal in adults)

                                                                                                            i.     Swyer James (recurrent viral infx in kids <8yo; unilateral hyperlucent small lung identified on CXR)

c.      Diffuse panbronchiolitis (exclusively Japanese)

d.     Follicular bronchiolitis (CVD like sjogrens, RA, HIV)

4.     B.O./constrictive bronchiolitis (swyer james in kids <8yo with unilat hyperlucent small lung identified on CXR)

a.     Etiology:

                                                                                                            i.     Recurrent viral infx

                                                                                                          ii.     Toxic fume exposure (smoking, NO2 silo worker, SO2, popcorn worker diacetyl)

                                                                                                         iii.     Drugs like penicillamine

                                                                                                         iv.     CVD, RA

                                                                                                          v.     Chronic transplant rejection (after lung transplant or GVHD after BM transplant)

b.     Features

                                                                                                            i.     Hyperlucent lobe/lung on inspiration

                                                                                                          ii.     Bronchial dilation and peribronchial thickening (due to constriction of distal bronchioles)

                                                                                                         iii.     Air-trapping only seen upon expiration (mosaic attenuation)

5.     Bronchitis

                                                vi.     MOSAIC ATTENUATION without centrilobular nodules or TIB

1.     Smokers

2.     Asthma/chronic bronchitis

3.     HP

4.     Follicular bronchiolitis

5.     B.O.

 

g.     Consolidation or airspace disease

                                                  i.     Diffuse airspace dz (*=acute)

1.     *water=CHF/ARDS (STD=shock, sepsis, trauma, drugs like crack cocaine)

2.     *pus=PNA

3.     *blood=hemorrhage (wegners, goodpasture, hemosiderosis)

4.     cells=lymphoma/BAC/OP

5.     fat=lipoid PNA

6.     protein=PAP

                                                 ii.     Upper-lobe predominant= “CASSET-P” cystic fibrosis, ank spond, sarcoidosis/silicosis, EG, TB, PCP

                                                iii.     Peripheral consolidation= “AEIOU” alveolar sarcoid, chronic Eos PNA, infarct, OP/COP, UIP

                                                iv.     Migratory/fleeting infiltrates= ABC acute eos PNA, ABPA, Aspiration, BOOP/COP, Chugg Straus (kids)

                                                 v.     Dense consolidations= amiadarone, talcosis (IV drug abuse), PMF (sarcoid/silicosis), amyloidosis, asbestos plaques (mimicker on CXR)

                                                vi.     Chronic infiltrates= BALLS BAC/lymphoma, Alveolar sarcoid, lipoid PNA/PAP, sequestration, chronic eos PNA

                                              vii.     Interstitial infiltrate=LIFE lymphangitic spread (adenoCA), infx (viral/atypical PNA), fibrosis (IPF), edema

                                             viii.     Infiltrate in kids= round PNA, plasma cell granuloma, CCAM, CLE, CDH, sequestration, duplication cyst, mets

 

h.     Cysts/Cavitation

                                                  i.     Emphysema (blebs vs bullae)

1.     Centrilobular vs Panlobular (lower lobe predominance; α-1-antitrypin def)

2.     Paraseptal

3.     Cicatricial (assoc with scarring or PMF)

                                                 ii.     Cysts

1.     Blebs (<1cm), bullae (>1cm), pneumatocele

2.     Cavitation

a.     Wall thickness

                                                                                                            i.     <4mm (93% b9)

                                                                                                          ii.     4-15mm (50% b9 and 50% malignant)

                                                                                                         iii.     >16 mm (99% malig)

b.     Inner wall appearance

                                                                                                            i.     Smooth (non-specific)

                                                                                                          ii.     Nodular=CA

                                                                                                         iii.     Shaggy=infx

c.      DDX cavitary lesions= “CT-SWAP” ca (primary SCC or secondary SCC like H&N males and cervical females), TB/fungal, septic emboli (feeding vessel sign), wegners (sinusitis) / RA (necrobiotic), abscess, aspergillosis (GG halo), papillomatosis, others (sarcoid, EG or PLCH, infarct), cystic bronchiectasis

d.     DDX cystic lesion with increased lung volumes= EG (male smokers >30yo), LAM (young females), CF, bullous emphysema, cystic bronchiectasis

e.     DDX thick cavity cyst with debris= infx (necrotizing PNA with pulm gangrene; TB/sarcoid/CF with mycetoma), infarct, CA, hydatid

f.      DDX cystic lesion kid= CLE, CCAM (I/II), CDH, bronchogenic cyst, pneumatocele, cavitary PNA/abscess/TB

                                                iii.     Bronchiectasis

1.     Cylindrical vs varicose (beaded) vs cystic (saccular)

2.     Bronchiectasis ddx

a.     Recurrent infx/aspiration (like TB, MAI=lady widemere)

b.     Finger-in-glove=CF/ABPA

c.      Congenital=immotile cilia (kartageners)/william-campbell  (Mounier Kuhn=tracheobronchomegaly)

d.     Fibrosis=traction bronchiectasis

e.     Emphysema

                                                iv.     Honeycombing

1.     Associated with interface sign=irreg margins of pleural and vessels; associate with traction bronchiectasis (corkscrew)

2.     Honeycombing ddx: “SCHARD”=sarcoidosis, CVD, chronic HP, asbestosis, RA, drug toxicity

3.     Lower lobe fibrosis= UIP or IPF, fibrotic NSIP assoc with chronic CVD (esp scleroderma), drug toxicity (“BAM”=bleomycin, amiodarone, methotrexate), asbestosis (parenchymal bands and curvilinear subpleural lines), RA (distal clav absorption), chronic emphysema

4.     End-stage lung dz= UIP, CVD (esp scleroderma), sarcoid, chronic HP, asbestosis, RA

 

i.       Others

                                                  i.     Air-trapping (emphysema, BO/swyer james, LAM, EG, CF)

                                                 ii.     LN (not uncommon in IPF esp if <15mm and only involves 1-2 nodal stations like paratracheal or subcarinal; usually responds to therapy like steroids)

1.     Low density LAD= TB/MAI, wipples/crohns, untreated lymphoma, mets (testicular etc)

2.     High density LAD= castlemans, carcinoid, Kaposi, LN mets from RCC (hemorrhage)

3.     Calcified LAD= TB, sarcoid/silicosis, treated lymphoma, papillary thyroid CA

                                                iii.     Effusion (pleural/pericardial)—think CVD or RA

                                                iv.     HIV “please test my CDfour”

1.     CD4>200: candida/Kaposi/TB (secomdary)

2.     CD4<200: PCP, TB (primary)

3.     CD4<100: Toxo

4.     CD4<75: MAC

5.     CD4<50: CMV/PMLE/Fungal

 

>>ILD classification


                                                  i.     Acute

1.     Hemorrhage

2.     Infx (viral, mycoplasma)

3.     Drug rxn

4.     Edema

                                                 ii.     Chronic

1.     ILD

2.     Inhalational (HP, asbestosis, silicosis)

3.     Smoking-related (emphysema)

4.     Lymphangitic spread

5.     CVD (including RA, sarcoidosis)

 

b.     Chronic fibrosing IP

                                                  i.     UIP (IPF)

1.     Age >50-70yo M>F

2.     More common in smokers or ex-smokers (may have emphysema in upper lobes)

3.     Patchy, bilateral peripheral/subpleural reticulations and honeycombing (with or without traction bronchiectasis)

4.     Basal-predominant

5.     Calcification within areas of fibrosis = dendriform pulmonary ossifications

6.     Some GG opacities but not the major feature (biopsy should be directed here)

7.     Poor prognosis

8.      “accelerated deterioration of UIP” if acutely worsening SOB and develop sig GG opacities

9.     5-10% develop lung CA (can hide in peripheral areas of honeycombing esp in lower lobes)

10.   “possible UIP” (absent honeycombing) and “inconsistent with UIP” àrequires biopsy

11.  If patient has known underlying process like RA, asbestosis, or CVD like scleroderma—don’t call it UIP!!! (instead call it chronic rheumatoid lung)

12.  Pirfenidone and Nintedanib (slows progression and improves survival)

13.  Honeycombing ddx: “SCHARD”=sarcoidosis, CVD, chronic HP, asbestosis, RA, drug toxicity

                                                 ii.     NSIP

1.     More common in females (younger pts ~40-50yo)

2.     Not associated with smoking 70% (usually associated with CVD)

3.     Cellular (better; pred GGO) vs fibrotic (GGO + retculations) vs mixed

4.     Lower lobe GG opacities with intra-lobular septal thickening (diffuse and confluent, not just peripheral like UIP)

5.     Classic “subpleural sparing” dorsally

6.     Lower lobe volume loss

7.     Usually no honeycombing (but may have traction bronchiectasis)

8.     Search for etiology like CVD, drug-induced, environmental exposure like HP (otherwise,  idiopathic)

9.     Acute exacerbation uncommon

10.  Some improve with tx while some remain stable for years (only minority progress to honeycombing aka progress to UIP)

 

c.      Smoking-related IP (some of these may co-exist)

                                                  i.     RB (asymptomatic)

1.     Asymptomatic smokers

2.     “Subtle” GG centrilobular nodules (more subtle than HP)

3.     Minimal GG  (aka dirty lung)

4.     Peribronchial thickening

5.     +/- air-trapping emphysema

                                                 ii.     RB-ILD (=RB + symptoms)

1.     Symptomatic heavy smokers (>30pack-years; 40-50yo)

2.     Findings of RB with more extensive GG opacities

3.     Peribronchial thickening

4.     Air-trapping (emphysema)

5.     Self-limiting

                                                iii.     DIP (not very common; less common than RBILD)

1.     M>F smokers (30-40yo)

2.     Bibasilar predominance GG with +/-fine reticulations (not much septal thickening)

3.     Classic “cystic changes within GG opacities”ßmay represent bleb related to emphysema

4.     No fibrosis

5.     Treat with cessation of smoking and steroids

                                               iv.     EG (pulmonary LCH)

1.     20-40yo smokers, M+F, whites more common

2.     Upper lobe pred nodules à thin-walled cyst à thick-walled cyst à irregular/bizzare-shaped cysts

3.     25% develop PTX

4.     10% develop extrapulm findings

5.     Part of Histiocytosis X: PLCH (adults), Letterer-Siwe (kids), Hand-Schuller-Christian (kids)

                                                 v.     Pulmonary fibrosis related to smoking

1.     Upper lobe honeycombing, septal thickening, and traction bronchiectasis

                                               vi.     CPFE (combined pulmonary fibrosis & emphysema)

1.     60-70yo male who are heavy smokers

2.     Upper lobe emphysema

3.     Lower lobe NSIP fibrosis

4.     Lung vol are preserved

5.     Decreased DLCO

6.     50% have pulm HTN

7.     Worse prognosis than UIP

 

d.     Acute/subacute IP

                                                  i.     OP/COP

1.     More common in non-smokers

2.     Assoc with infx, drugs, autoimmune dz (esp myositis syndromes)

3.     Acute onset <3mos of flu-like syndrome (SOB/cough/fever/chills/wtloss)

4.     Peribronchial and subpleural consolidations (“polygonal shaped” or irregular)—can be migratory (may have lobar predominance, not diffuse)

5.     GGO (crazy paving)

6.     Centrilobular nodules

7.     Classic “reverse halo” or “atoll” sign (rare but specific)

8.     Involve mid to lower lung

9.     May have small effusion

10.  Can be idiopathic or assoc with CVD, drugs, aspiration, infx

11.  Restrictive lung disease like other ILDs

12.  Excellent response to steroids (with complete recover in most pts)

13.  Main DDx is chronic eos PNA can look very similar (look for peripheral eso)!!

                                                 ii.     DAD/AIP (Hamman rich)

1.     AIP= idiopathic ARDS (which responds to steroids which are generally avoided in infectious ARDS)—if have patient with ARDS who is not responding to conventional tx, consider this diagnosis

2.     Acute (<1wk) fulminant  (ICU patients)

3.     Appearance similar to ARDS but higher mortality

4.     Diffuse confluent GG sparing CPAàproliferative/organizingà anterior upper lobe fibrosis fibrotic with traction bronchiectasis

 

e.     Others entities

                                                  i.     LIP

1.     B9 lymphoproliferative disorder with lymphocytic infiltrates

2.     Exclusively in Sjogrens or RA (adults) or AIDS (kids<13yo)

3.     Retriculonodular pattern, GGO, and cysts

a.     Peribronchovascular and centrilobular nodules

b.     GGO

c.      Peribronchovascular/subpleural/randomly-distributed cysts

4.     Associated with monoclonal or polyclonal gammopathy

5.     May progress to lymphoma (5%)

                                                 ii.     HP (EAA)

1.     Organic antigen=EAA (farmer, bird fancier, pigeon breeder etc)

2.     Inorganic antigen=pneumoconiosis

3.     Acute (lower lobe pred; diffuse airspace dz w/ GGO; mimics edema or ARDS)=symptoms <1mo

4.     Subacute (symptoms wks to 4mos)

a.     Upper to mid lung

b.     GG Centrilobular nodules (classic—ddx is hemosiderosis or RBILD if subtle)

c.      Head-cheese (mosaic attenuation)

5.     Chronic (fibrosis in similar pattern as the head-cheese pattern of subacute dz with mosaic attenuation and air-trapping)=symptoms >4mos to yrs

6.     Smoking is protective (tell the pigeon-fancier to start smoking!)

                                                iii.     PPFE (pleuroparenchymal fibroelastosis)

1.     50-60yo (usually post-lung or BM transplant)

2.     Similar to fibrotic TB in upper lung zone

3.     Peripheral upper lobe fibrosis, pleural thickening, and upward retraction of hila

 

f.      CVD (usually associated with NSIP)

                                                  i.     RA (constrictive bronhiolitis and  BOOP may co-exist)

1.     Pleural/pericardial effusion

2.     Necrobiotic nodules

3.     Distal clavicular erosions

                                                 ii.     Scleroderma

1.     Dilated eso

2.     Pulm HTN

3.     Calcinosis (calc arounds joints if CREST syndrome)

                                                iii.     SLE (lupus)

1.     Fibrosis uncommon

2.     Pleural/pericardial effusion

3.     Pulm HTN

                                                iv.     Sjogrens

1.     Rare to have IPF

2.     LIP

                                                 v.     DM/PM

1.     Soft tissue calcifications in DM

 


FLEISCHNER SOCIETY NODULE F.U. GUIDELINES  



                                           
                         solid pulmonary nodule followup guidelines
semi solid pulmonary nodule followup guidelines



   .

LUNG RADS V.1  



         LUNG RADS VERSION 1 LOW DOSE CT CHEST SCREENING NODULE FOLLOW UP GUIDE                                  
                         
Lung Rads screening lung nodule low dose CT chest version1



   .

LYMPH NODE CLASSIFICATION (IASLC 2009)  



                    MEDIASTINAL LYMPH NODE STATIONS CLASSIFICATION IASLC 2009                       
                         

ZONE

STATION

DESCRIPTION

BOUNDARIES

SUPRACLAV-ICULAR

1

Low cervical, supraclavicular, sternal notch

Midline of trachea serves as border btwn 1L and 1R.

Below lower margin of cricoid; above upper margin of manubrium and clavicles.

UPPER (SUPERIOR

MEDIASTINAL)

2 R/L

Upper paratracheal (adjacent to great vessels)

Left lateral border of trachea serves as border btwn 2L and 2R.

2L=btwn upper border of manubrium to upper margin of aortic arch.

2R=btwn upper border of manubrium to lower margin where left brachiocephalic vein intersect trachea.

3 A/P

3A=Prevascular (anterior mediastinal)

3P=Prevertebral (retrotracheal)

From sternal notch to carina.

Prevascular=located anterior to left brachiocephalic vein and within anterior mediastinum (not left lateral of asc aorta/arch; ant to ant border of SVC).

Prevertebral=located behind eso adj to vertebral body (not adj to trachea).

4 R/L

Lower paratracheal

Left lateral border of trachea serves as border btwn 4L and 4R.

4L=above upper margin of left main PA (medial to lig arteriosum)—includes precarinal node. 4R=above lower margin of azygos (carina).

AORTO-

PULMONARY

5

Subaortic (AP window)

AP window nodes lateral to lig arteriosum (below inferior margin of aortic arch).

6

Para-aortic (phrenic)

Anterior and left lateral to ascending aorta or aortic arch (btwn inf margin of aortic arch and sup margin of LPA).

SUBCARINAL

7

Subcarinal

Underneath carina (above superior margin of left lower lobe bronchus on the left; above inferior margin of bronchus intermedius on the right).

LOWER (INFERIOR MEDIASTINAL)

8

Paraesophageal (below carina)

Below carina and adjacent to wall of esophagus (excluding subcarinal nodes).

9

Pulmonary ligament

Between inferior pulm vein to diaphragm.

HILAR/

INTERLOBAR

10 R/L

Hilar

Adjacent to mainstem bronchi and hilar vessels until interlobar region.

11 R/L

Interlobar

Between origin of lobar bronchi.

PERIPHERAL

12 R/L

Lobar (peribronchial)

Adjacent to lobar bronchi.

13 &14 R/L

Segmental/sub-segmental

(peribronchial)

Adjacent to subsegmental bronchi.

OTHERS

Internal mammary; Paravertebral; Paracardiac (epicardiac nodes)





   .

INTERSTITIAL LUNG DISEASE PATTERNS & DDX

 
INTERSTITIAL LUNG DISEASE (ILD) PATTERN APPROACH SIMPLIFIED ALGORITHM FOR HI RES CT (HRCT)

LINES

1. Interlobular septal thickening:

    a. smooth (water=edema; blood=hemorrhage; pus=infx; protein=PAP)

    b. nodular (same differentials as perilymphatic nodules)

    c. irregular (ILD or other fibrosing lung disease)

    **Upper lobe predominant ddx: “CASSET-P=cystic fibrosis; ankylosing spondylitis; silicosis; sarcoidosis; EG; TB; PCP

   (inhaled pentamidine)

    **Lower lobe predominant ddx: “BAURDLAC”=bronchiectasis; aspiration; UIP/NSIP(fibrotic); RA; drug toxicity;

    lymphangitic spread; asbestosis; CVD like scleroderma; CPFE or combined pulmonary fibrosis and emphysema

2. Intralobular reticulations (net-like fibrosis): suggests ILD or other fibrosing lung disease

3. Bronchovascular thickening

4. Subpleural line and parenchymal bands (asbestosis; atelectasis etc)

 

NODULES

Micronodules (3-5mm)

1. Centrilobular

    a. solid without TIB (pneumoconiosis; EG)

    b. solid with TIB (“STAB”= smokers RB/RBILD; endobronchialTB/MAC; aspiration; bronchiolitis; bronchoPNA; BAC)

    c. GG or ill-defined (subacute HP if non-smoker; RB/RBILD if smoker; others include hemosiderosis and acute varicella   

    PNA)

2. Perilymphatic (sarcoidosis; lymphangitic spread; LIP)

3. Random (“METS-V”=mets like renal/thyroid/melanoma; EG; miliary 1-3mm TB/fungal; sarcoid/silicosis; disseminated viral infx)

**Calcified nodules ddx: old TB/fungal; alveolar microlithiasis; malig calcifications; healed varicella; silicosis; mets (mucinous/osteo-/chondrosarcoma)

**GG halo nodules ddx: hemorrhagic mets (chorioCA etc); invasive aspergillosis; kaposi

 

GGO

1. Acute GGO (water=edema/ARDS; blood=hemorrhage; pus=atypical infx like CMV in HIV and post-transplant; acute HP; AIP)

2. Chronic GGO (“ABCDEH”= PAP crazy paving; BOOP; BAC; PCP; DIP/NSIP; drugs “BAM-CN”; edema; HP head-cheese; hemorrhage)

**Crazy Paving ddx: PAP (20-50yo smokers); ARDS; AIP; edema/hemorrhage; infx/PNA; BAC

**History helps: hemoptysis (hemorrhage); immunocompromised (CMV/PCP); exposure (HP); CVD (NSIP); drugs (“BAM”=bleomycin, amiodarone, methotrexate, cyclosphosphamide; nitrofurantoin)

 

MOSAIC ATTENUATION (not GGO)

Note: Mosaic attenuation is an inspiratory HRCT finding while air-trapping is an expiratory HRCT finding! To differentiate from GGO of parenchymal origin, look at lucent areas on inspiratory view for abnormal small vessels, abnormal dilated/thickened airways, and air-trapping on expiratory views. Also septal thickening can suggest GGO of parenchymal origin.

PFTs in small airways disease=decreased VC; decreased FEV1; increased RV; normal FEV1/VC ratio; normal TLC

1. Small airways dz (with bronchial wall thickening; bronchiolectasis, +/-centrilobular nodules and air-trapping on expiration): inflamm/infx bronchiolitis (including follicular bronchiolitis in CVD/RA/HIV or pan-bronchiolitis in Japanese); smokers (RB/RB-ILD); HP (head-cheese); constrictive bronchiolitis or B.O. (repeated viral infx vs toxic fume inhalation vs chronic transplant rejection); asthma

2. Small vessels dz: chronic PE; vasculitis

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AIR TRAPPING ON EXPIRATORY CT

1. With normal inspiratory CT: Normal patient (with ≤3 adjacent secondary lobules); Asthma and chronic bronchitis; B.O. (cryptogenic; post-infx like viral or mycoplasma; toxic inhalation; GVHD; lung transplant; RA; IBD; pencillamine therapy)

2. With abnormal inspiratory CT with interstitial lung changes: HP; Sarcoidosis; Toxic inhalation; Emphysema; LAM and EG; Others rare stuff like HIV and Churg strauss

3. With abnormal inspiratory CT with bronchiectasis: CF; ABPA; MAI; Swyer James; Chronic aspiration; Tracheobronchomalacia

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CONSOLIDATION

1. Acute (water=edema; blood=hemorrhage like wegners/goodpastures/hemosiderosis; pus=PNA)

2. Chronic (cells=BAC/lymphoma; protein=PAP; lipid=lipoid PNA)

3. Peripheral (“AEIOU”=Alveolar sarcoid; chronic eso PNA; infarct; BOOP; UIP)

4. Migratory (“ABC”=acute eso PNA; ABPA; aspiration; BOOP; Churg-strauss in kids)

 

CYSTS 

Thin walled <5mm usually b9; Thick walled >15mm more concerning for malignancy

1. Diffuse cysts: EG (male smokers); LAM (female); LIP (sjogrens/kids with HIV); emphysema

2. Cavitary lesions: “CT-SWAPO”=CA; cystic bronchiectasis; septic emboli; wegners/RA; abscess; aspergillosis; papillomatosis; others like EG/sarcoid/infarct

3. Bronchiectasis: MAI; CF; ABPA; aspiration; traction bronchiectasis (fibrosis); congenital (WC, MK, immotile cilia syndrome)

4. Honeycombing: “U-SCAR-HD”=UIP; sarcoidosis; CVD; asbestosis; RA; HP chronic; drug toxicity

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INTERSTITIAL LUNG DISEASE PATTERN BASED DIFFERENTIAL

LOCATION

UPPER LOBE PRED

CASSET-PH

-Cystic fibrosis

-Ankylosing spondylitis

-Silicosis

-Sarcoidosis

-EG

-TB/fungal

-PCP (inhaled pentamidine)

-HP

LOWER LOBE PRED

BAURDLAC”

-Bronchiectasis

-Aspiration

-UIP/NSIP(fibrotic)

-RA

-Drug toxicity

-Lymphangitic spread

-Asbestosis

-CVD like scleroderma; CPFE (combined pulmonary fibrosis and emphysema)

LINES

INTERLOBULAR

SEPTAL THICKENING

SMOOTH

water=edema

blood=hemorrhage

pus=infx

protein=PAP

NODULAR

same differentials as perilymphatic nodules

IRREGULAR

 UIP or any chronic fibrosing lung disease

NODULES

(MICRO)

CENTRILOBULAR

SOLID w/o TIB

-Pneumoconiosis

-EG

SOLID w/ TIB

STAB”

-Smokers RB/RBILD

-Endobronchial TB/MAC

-Aspiration

-Bronchiolitis

-BronchoPNA

-BAC

GG

-Subacute HP if non-smoker

-RB/RBILD if smoker

-Others (hemosiderosis; acute varicella PNA)

PERILYMPHATIC

-Sarcoidosis

-Lymphangitic spread

-LIP (kids with HIV or adults with Sjogrens)

RANDOM

METS-V”

-Mets like renal/thyroid/melanoma

-EG

-Miliary 1-3mm TB/fungal

-Sarcoid/silicosis

-Disseminated viral infx

GGO

ACUTE

water=edema/ARDS

blood=hemorr

pus=atypical infx like CMV in HIV/post-tx

acute HP

AIP

CHRONIC

ABCDEH”

-PAP crazy paving

-BOOP

-BAC

-PCP

-DIP/NSIP

-Drugs BAM-CN”

-Edema

-HP head-cheese

-Hemorrhage

CRAZY PAVING

-PAP

-ARDS/AIP

-Edema

-Hemorrhage

-PNA

-BAC

MOSAIC

ATTEN.

SMALL AIRWAYS

DISEASE

-Inflamm/infx bronchiolitis (including follicular bronchiolitis in CVD/RA/HIV or pan-bronchiolitis in Japanese)

-Smokers (RB/RB-ILD)

-HP (head-cheese)

-B.O. (cryptogenic; post-infx like viral or mycoplasma; toxic inhalation; GVHD; lung transplant; RA; pencillamine therapy)

-Asthma and chronic bronchitis

SMALL VESSEL

DISEASE

-Chronic PE

-Vasculitis

AIR TRAPPING

(ON EXPIR.

CT)

WITH NORMAL INSPIRATORY CT

-Normal patient (≤3 adjacent secondary pulmonary lobules)

-Asthma and chronic bronchitis

-B.O. (cryptogenic; post-infx like viral or mycoplasma; toxic inhalation; GVHD; lung transplant; RA; pencillamine therapy)

WITH INTERSTITIAL CHANGES ON INSPIRATORY CT

-Emphysema

-HP

-Sarcoidosis

-Toxic inhalation

-LAM

-EG

WITH BRONCHIECTASIS
ON INSPIRATORY
CT

-MAI

-CF

-ABPA
-
Swyer James

-Chronic bronchitis

-Tracheobronchomalacia

CONSOLI-

DATION

ACUTE

water=edema

blood=hemorrhage like wegners/goodpastures/hemosiderosis

pus=PNA

CHRONIC

cells=BAC/lymphoma

protein=PAP

lipid=lipoid PNA

other (BOOP, Chronic Eos PNA)

PERIPHERAL

AEIOU”

-Alveolar sarcoid

-Chronic Eso PNA

-Infarct

-BOOP

-UIP

MIGRATORY

ABC”

-Acute Eso PNA

-ABPA

-Aspiration

-BOOP

-Churg-strauss in kids

CYSTS

DIFFUSE CYSTS

-Emphysema

-Cystic bronchiectasis

-EG (male smokers)

-LAM (female)

-LIP (sjogrens/kids with HIV)

CAVITARY LESION

CT-SWAPO”

-CA

-Cystic bronchiectasis

-Septic emboli

-Wegners/RA

-Abscess

-Aspergillosis

-Papillomatosis

-Others like EG/sarcoid/infarct

BRONCHIECTASIS

-MAI

-CF

-ABPA

-Aspiration

-Chronic infx

-Congenital (WC, MK, immotile cilia)

-Traction bronch (fibrosis)

HONEYCOMBING

U-SCAR-HD”

-UIP

-Sarcoidosis

-CVD

-Asbestosis

-RA

-HP chronic

-Drug toxicity

 INTERSTITIAL LUNG DISEASE PATTERNS DIFFERENTIAL DIAGNOSIS SIMPLIFIED APPROACH CHART DDX INTERSTITIAL PNEUMONIAS ILD HRCT SIMPLIFIED REVIEW AIP UIP NSIP DIP LIP RBILD HP EG SEPTAL THICKENING GROUND GLASS OPACITIES CYSTS HONEYCOMBING


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